condition mean min max ZT0-3 7.986423 7.986423 7.986423 ZT4-7 9.6524675 9.6524675 9.6524675 ZT8-11 9.733895 9.733895 9.733895 ZT12-15 10.827874 10.827874 10.827874 ZT16-19 8.716780499999999 8.716780499999999 8.716780499999999 ZT20-23 8.325908 8.325908 8.325908